To use the mental ray translator and renderer, you must first choose mental ray as the production renderer, as described the "Procedures" section below. Once you have chosen mental ray rendering, the Render Setup dialog displays panels and rollouts that control the mental ray renderer.
-
Main toolbar >
(Render Setup) > Render Setup dialog > Common panel > Assign Renderer rollout > Choose NVIDIA mental ray as the Production renderer.
Common Parameters Rollout
When you render with mental ray, controls on the Render Setup dialog 
Common panel Common Parameters rollout remain the same, and function just as they do with the default scanline renderer.
Limitations
The mental ray renderer does not support certain rendering features, as described here.
- Output dithering options aren't supported (in Main menu Customize Preferences Preference Settings dialog Rendering panel Output Dithering group).
- The mental ray renderer does not fully support G-buffer options in post processing and image file output. The mental ray renderer generates all required G-buffer channels, but does not include transparency information. If two transparent objects overlap each other, the mental ray render generates information only for the frontmost object.
- When you use a bitmap as an environment (that is, as a background), the mental ray renderer samples and filters it. This can result in unwanted blurring. To prevent background blurring, render the scene against a solid-color background, and then composite the rendered scene with the background image.
- Sometimes when you render objects that have no thickness, or an Extrude modifier with zero thickness, the mental ray renderer generates rendering artifacts that appear as streaks. In some cases, you can fix this by turning on Force 2-Sided on the Render Setup dialog's Common Parameters rollout. If the streaks persist, give the object or the Extrude modifier a nonzero thickness.
Procedures
To use the mental ray renderer:
- Choose Rendering menu Render Setup. 3ds Max opens the Render Setup dialog.
- On the Common panel, open the Assign Renderer rollout, then click the “...” button for the Production renderer.
3ds Max opens the Choose Renderer dialog.
- On the Choose Renderer dialog, highlight mental ray Renderer and then click OK.
Now, when you render, the Render Setup dialog appears with the mental ray controls. You can choose to render the scene with the built-in mental ray renderer, or simply to translate the scene and save it in an MI file that you can render later, perhaps on a different system. Controls for choosing whether to render, save to an MI file, or both, are on the Translator Options rollout.
To make the mental ray Renderer the default renderer for new scenes:
- After you make the mental ray renderer the active production renderer, click Save As Defaults on the Assign Renderer rollout.